Continuous methanogenesis of black liquor of pulp and paper mills in an anaerobic baffled reactor using an immobilized cell system

An anaerobic baffled reactor together with an immobilized cell system has been proposed for methanogenesis of the black liquor from pulp and paper mills in a continuous system. A maximum chemical oxygen demand reduction of 50%, and biogas generation of 10 L d^?1, having methane content of 66% (v/v) at an organic loading rate (OLR) of 7 kg m^?3 d^?1 with hydraulic retention time of 2 days, were recorded. OLR values higher than 7 kg m^?3 d^?1 were toxic to methanogenesis and destabilized the reactor system. Copyright © 2006 Society of Chemical Industry     

玻璃纤维理化性能对生产过程影响的研究

玻璃纤维物理性能主要包括硬挺度、断裂强度、可燃物含量、含水率、线密度等一系列指标,对玻璃纤维理化性能进行充分的了解,能够有利于稳定生产、拍导生产、质量控制。本文首先分析了玻璃纤维的物理化学特点,其次,从质量控制、稳定和指导生产三个方面就玻璃纤维理化性能对生产过程影响进行了深入的研究,提出了自己的思考和观点,具有一定的参考价值。     

苇浆回用性能的研究

本文研究了漂白硫酸盐苇浆在反复回用过程中物理化学性能的变化规律。试验表明，随着回用次数增加，聚戊糖含量、保水值、纸页紧度、抗张与耐破强度、耐折度逐渐降低，且对原浆打浆有较大的下降趋势；平均聚会度、相对结晶指数与散射系数具有增加的总趋势；纤维平均长度由于细小级分流失有所增加；零距裂断长变化较小。打过浆与未打浆苇浆在回用过程中抗张指数与紧度均成对数直线关系，其斜率分别为2．481和2.09。     

甲醇汽油的理化性能研究

通过对甲醇汽油馏程、蒸汽压、实际胶质、抗相分离性能等关键理化性质的进一步分析,提出了目前调制甲醇汽油所存在的主要技术问题。     

Formation and evolution of the carbon black network in polyethylene/carbon black composites: Rheology and conductivity properties

We report a detailed investigation on the effect of carbon black (CB) morphology on network formation and evolution in high‐density polyethylene/CB composites. There were three types of networks in our study, the electrical network in the solid state and the electrical and rheological networks in the melt state. The evolution of the network in the polymer melt was traced by simultaneous electrical resistivity (R) and dynamic rheology testing. An oscillation strain sweep was used to investigate the network stability with a large strain. We found that with high‐structure CB with a branched morphology, it was easier to form a filler–polymer or filler–filler network than with low‐structure CB with a spherical morphology in the composite melt. The high‐structure CB network was more stable with a large strain compared to the low‐structure one. Meanwhile, the low‐structure CB aggregates had stronger capability of movement and re‐aggregation in the polymer melt. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39953.     

Evaluation of emu oil extraction methods and their effects on physical and rheological behavior

In this study we evaluated the efficiency of six extraction methods for emu fat based on the quantification of yield, color, density, refraction index, and rheological behavior. Both physical methods (Bain Marie, rotary evaporator, fusion, ultrasound, and microwave) and chemical methods (solvents) were evaluated. Oil properties were compared with commercial emu oil as a reference. Solvent‐based extraction produced the greatest yield (72.8%). Among the physical methods, the greatest yield was produced by the ultrasound method (42.8%). In general, properties were similar to those reported for vegetable oils. The rotary evaporator method showed the greatest difference in total color (ΔE) in comparison with a commercially‐produced reference, while the fusion method showed the smallest ΔE. No statistically significant differences were found between the density and refraction index of the treated samples and those of the reference. Kinematic viscosity increased significantly in samples extracted via microwave method. All samples displayed pseudoplastic behavior. The data showed a good fit to the power law model (R² > 0.90). The consistency coefficient and flow behavior index were determined for all methods. Practical applications: Therapeutic applications for oil have been posited for emu oil. In pharmaceutical products, oils are used as emollients and as carriers for medicinal substances. The practical importance of an oil depends on its physical properties, thus a thorough understanding of those physical properties is very important for identifying potential applications. These properties are affected by the extraction method employed; the present paper evaluates the effects of a range of extraction methods on yield efficiency, as well as physical and rheological properties. Novel extraction methods such as ultrasound and microwave are also evaluated in this study.     

Thermal analysis of borogypsum and its effects on the physical properties of Portland cement

Borogypsum, which consists mainly of gypsum crystals, B₂O₃ and some impurities, is formed during the production of boric acid from colemanite, which is an important borate ore. In this study, the effect of borogypsum and calcined borogypsum on the physical properties of ordinary Portland cement (OPC) has been investigated. The calcination temperature and transformations in the structures of borogypsum and natural gypsum were determined by differential thermal analysis (DTA), thermogravimetric analysis (TGA) and X-ray diffraction (XRD) techniques. Thermal experiments were carried out between ambient temperature and 500 °C in an air atmosphere at a heating rate of 10 °C min⁻¹. After calculation of enthalpy and determination of conversion temperatures, borogypsum (5% and 7%), hemihydrate borogypsum (5%) and natural gypsum (5%) were added separately to Portland cement clinker and cements were ground in the laboratory. The final products were tested for chemical analysis, compressive strength, setting time, Le Chatelier expansion and fineness properties according to the European Standard (EN 196). The results show that increasing the borogypsum level in Portland cement from 5% to 7% caused an increase in setting time and a decrease in soundness expansion and compressive strength. The cement prepared with borogypsum (5%) was found to have similar strength properties to those obtained with natural gypsum, whereas a mixture containing 5% of hemihydrate borogypsum was found to develop 25% higher compressive strength than the OPC control mixtures at 28 days. For this reason, utilization of calcined borogypsum in cement applications is expected to give better results than untreated borogypsum. It is concluded that hemihydrate borogypsum could be used as a retarder for Portland cement as an industrial side. This would play an important role in reducing environmental pollution.     

Joint effects of rotational extrusion and TiO2 on performance and antimicrobial properties of extruded polypropylene copolymer pipes

In this study, effects of titanium dioxide (TiO₂) and rotation extrusion on structures and properties of polypropylene random copolymer (PPR) pipes were investigated. The experimental results showed that with the presence of TiO₂, not only the antibacterial ability of PPR pipe was improved significantly but also the toughness was enhanced since a large number of PP chains were promoted to crystallize into β‐form crystals. Furthermore, when rotation extrusion was introduced into the process of PPR pipe, the drag hoop flow caused by mandrel and die rotation was superposed on the axial flow, so the polymer melts in the annulus underwent a helical flow and its flow direction deviated from the axis to drive the molecular orientation off the axial direction, bringing out the increased hoop strength. As a result, PPR pipe with excellent performance was prepared under the combined effect of rotation extrusion and TiO₂. The antibacterial activity was 99.2%, the hoop tensile strength reached 27.5 MPa, 67.7% higher than that of the convention‐extruded PPR pipe with TiO₂, and the impact strength was 10.9 kJ/m², increased by 81.6% compared to that of the rotation‐extruded pure PPR pipe. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42410.     

Some physical properties of Canadian coals and their effects on coal reactivity

The pore volume, surface area and compressibility of eleven Canadian coals, varying in rank from lignite to semianthracite, have been determined by mercury porosimetry, gas adsorption method and relations derived from helium and mercury densities. The total pore volume was measured in the diameter range of 0.2 nm–2.98 μm, which was subdivided into two groups, namely the micropore region (< 0.0036 μm) and the combined meso- and macropore region (0.0036–2.98 μm). It has been determined that the porosity of the eleven coals studied varies from 2 to 39%. It has been found that the total pore volume, micropore volume, surface area and the apparent compressibility of these coals decrease with increase in the carbon content, or the rank of the coals. The effect of the total pore volume, micropore volume and surface area on chemical reactivity of the coal is discussed separately. A good correlation was obtained between the carbon content and helium density of the coal after correction is made for the mineral content.     

Effect of the carbon black content on the thermal,rheological and mechanical properties of thermoplastic polyurethanes

Different mixtures of thermoplastic polyurethane (PU) with different amounts of nanometric carbon black (CB) were prepared by mechanical stirring in organic solvent, and their thermal, rheological, viscoelastic and mechanical properties were investigated. The rheology of the PU–CB mixtures in methyl ethyl ketone was optimized, allowing good dispersion of the CB in the polyurethane matrix once the solvent was removed; an increase in the number and size of carbon black aggregates in the polyurethane matrix was obtained by increasing the carbon black loading. Addition of carbon black improved the rheological and viscoelastic properties of the polyurethane, and the larger was the carbon black content, the higher was the storage modulus and the lower was the tanδ value. Moreover, the addition of higher amounts of CB changed the viscoelastic behaviour of the polyurethane, which became mainly elastic over all temperature range. On the other hand, the addition of CB loadings up to 12 wt% increased the thermal stability of the polyurethanes and increased the elongation-at-break without noticeable reduction in the tensile strength.     

Preparation of multifunctional thiol‐ and acrylate‐terminated polyurethane: A comparative study on their properties in UV curable coatings

The multifunctional thiol‐ and acrylate‐terminated polyurethane (PU) has been successfully prepared for using as the main resin in the UV curable coatings. The structure and molecule weight of prepared PUs were analyzed by fourier transformed infrared spectroscopy (FTIR) and gel permeation chromatography, respectively. The results showed that the different terminal multifunctional groups have been grafted onto the PU and their difference in molecule weight was significant. Used as the main resin in coatings, the curing kinetic and percentage conversion of the different UV curing coatings system were investigated by real‐time FTIR method, and the effects of terminal functional groups and photoinitiator on the final conversion percentage and conversion rate were also compared. It is observed that the thiol‐terminated PU had higher conversion speed and final conversion percentage due to the remarkable effect of mercapto groups on reducing oxygen inhibition during UV curing process. The shrinkage, viscosity, and adhesion of UV curable coatings with thiol‐ and acrylate‐terminated PUs were also investigated and compared, and the results indicated that the former exhibited lower shrinkage and higher adhesion performances than the latter, along with the lower viscosity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40740.     

Investigation of the effects of perlite additive on some comfort and acoustical properties of polyester fabrics

Natural perlite material was added for the first time into a polyester filament yarn structure. The water absorption and heat and sound insulation properties of the fabrics produced from textured and twisted polyester yarns containing 1.25% perlite additive were tested, and the results were compared with those obtained on the fabrics produced from reference polyester yarns. Although there are differences between the mechanical properties of the polyester yarns, the yarns including perlite remained within commercial usage limits. The thermal resistance values of polyester sateen fabrics obtained from perlite‐containing yarns were higher than those of the reference fabrics. The contribution of perlite led to a marked improvement, especially in the hydrophilicity and sound insulation of the polyester fabrics. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43128.     

Modification of dry‐spun Suplon polyimide fibers by mixed‐acid oxidation and their effects on the properties of polypropylene‐resin‐based composites

In this study, the effects of mixed‐acid oxidation on the contents of surface elements, morphology, fiber fineness, mechanical properties, mass change rate, chemical structure, and microaggregate structure of dry‐spun Suplon polyimide (PI) fibers were systematically investigated with wet chemical treatment with HNO₃/H₂SO₄. Experiments investigating both the improvement in the O/C ratio of the fiber surface elements and the changes in other performance features were conducted through the functional modification of the fibers. Meanwhile, the causes of specific changes in the mechanical properties of the oxidized PI‐fiber‐reinforced polypropylene‐resin‐based composites were studied and are discussed. The results of this study demonstrate that the treatment of the fibers with HNO₃/H₂SO₄ mixed‐acid oxidation resulted in significant changes in the properties of the fibers; these changes included an uneven surface, increased specific surface area and surface roughness, a locally etched surface, increased surface energy and O/C ratio, an enhanced wettability, an increased fiber fineness, reduced mechanical properties, and a mass gain in the fibers. Although the chemical structures of the fibers treated by oxidized HNO₃/H₂SO₄ were not significantly changed compared to those of the untreated fibers, the microscopic aggregation of the treated fibers changed to some degree, and the ratio of the amorphous regions significantly increased. Taken together, the functional modification of the PI fiber surface was achieved efficiently through the use of a suitable HNO₃/H₂SO₄ oxidation process and with other performance features of the fibers taken into account. This was favorable for the enhancement of the interfacial properties of the polypropylene fibers and the matrix resins, and thus, the modification improved the mechanical properties of the composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44932.     

Polymer compounds based on the three-component blend PP-EPDM-oil: effect of their structure on physical properties

The variation of structure and properties of a triple blend of polypropylene (PP), ethylene-propylene-diene monomer rubber (EPDM), and oil with mixing conditions was studied. The structure and physical properties of this blend are mainly determined by the intermolecular interaction of EPDM and PP components. The interaction depends on the EPDM/PP ratio at the molecular level and on the mixing regime. The optimal mixing conditions that determined the better physical properties of these blends were defined.     

Water vapor sorption and diffusion in wheat straw particles and their impact on the mass transfer properties of biocomposites

This work intends to decipher the role of hydrophilic fillers, wheat straw fibers (WSF), on the water vapor transfer properties (sorption and diffusion) of biocomposites based on poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate), (PHBV) as matrix. Transfer in biocomposites, measured using dynamical vapor sorption measurement, is correlated to the transfer properties of each individual constituent and to the specific structural arrangements induced by the presence of particles inside the matrix. Increasing amounts of WSF particles in the PHBV matrix lead to an increase of the water vapor sorption (WVS) of the resulting composites. This is attributed to the high sorption of hydrophilic WSF as compared to that of the neat PHBV matrix. Water vapor diffusion in composites (around 0.13 × 10^?11 m² s^?1 at 20°C whatever the filler content) is always lower than in the neat matrix (0.26 × 10^?11 m² s^?1) although wheat straw displays high diffusivity values (1.84 × 10^?11 m² s^?1). Such unexpected behavior is related to (1) changes of structure and properties of the WSF particle once embedded in the PHBV matrix, (2) changes in the polymer matrix structure and properties in contact with fibers, and also (3) to the representativeness of the filler diffusivity, which is difficult to appraise. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43329.     

The electropolymerization of several poly(3‐methylthiophene) films in the same used solution and its consequence in their properties

The effect of the electropolymerization of seven poly(3‐methylthiophene) (P3MT) films in the same used monomer solution have been investigated. Cyclic voltammetry, UV‐visible, scanning electron microscopy, and electrochemical impedance measurements were carried out to understand the effect of the solution reusing on the polymer electrochemical properties. The obtained results show that, as the solution is reused, the polymerization rate increase and the charge in of the cyclic voltammetry decrease. Besides, there are important changes in the sample's morphologies, with the increase of the synthesis number, the amount of fibers increase and this leads to lower the conductivity of the polymer film. In agreement to this, the impedance data analysis shown important changes in the interfacial electronic parameters, i.e., changer transfer resistance and double‐layer capacitance, used to describe the films. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44368.     

Effect of surfactant on EG dispersion in EVA and thermal and mechanical properties of the system

The influence of expanded graphite (EG) and sodium dodecyl sulfate (SDS) modified EG on the structure, thermal stability, and mechanical properties of ethylene vinyl acetate (EVA) was investigated in this study. The EVA filled with EG platelets, with and without anionic SDS modification, was prepared by melt mixing using a Brabender Plastograph mixer. The extent of dispersion and morphology of the composites were characterized using scanning electron microscopy (SEM), optical microscopy (OM), and X‐ray diffraction (XRD). The optical microscopy results show better distribution of the modified EG platelets in the EVA matrix, while the SEM results show an improved interfacial adhesion between the polymer and the SDS‐EG particles. Both the EVA18 copolymer and the EG platelets have monoclinic phases, and both EG and SDS do not seem to have any influence on the melting and crystallization behavior of the EVA18. The addition of EG enhanced the thermal stability of EVA18, and this stabilizing influence was further improved when the EG was treated with SDS. All the tensile properties of EVA/EG improved after surface modification. The storage modulus of EVA generally increased with increasing both the unmodified EG and the SDS modified EG content. There was a shift in the T_g to higher temperatures with an increase in both the EG and modified EG content. The α‐relaxation peak in the SDS modified EG curves was less intense than the β‐relaxation peak, even for the untreated EG composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41352.     

Surface modification of graphitized carbonaceous materials by electropolymerization of thiophene and their effects on electrochemical properties

Highly oriented pyrolytic graphite (HOPG) and graphitized carbonaceous thin films prepared by plasma-assisted chemical vapor deposition (PACVD) were surface-modified by electropolymerization of thiophene. The electrochemical properties of the carbonaceous materials were studied by cyclic voltammetry and ac impedance spectroscopy. Irreversible cathodic current of the carbonaceous materials above 0.5 V (vs. Li/Li⁺) in the cyclic voltammograms significantly decreased by electropolymerization of thiophene, indicating that electropolymerization of thiophene suppress the decomposition of electrolytes on the carbonaceous materials. On the Nyquist plots, a semi-circle due to surface film resistance was observed, and the value significantly decreased at around 1.5 V. At potentials below 0.9 V, another semi-circle appeared in the middle to lower frequency region, which was assigned to the charge transfer resistance due to lithium-ion transfer at the surface-modified carbon electrode/electrolyte interface. The charge-transfer resistances were dependent on electrode potentials. The activation energy for lithium-ion transfer through interface between the surface-modified HOPG electrode and electrolyte was evaluated, and the value was almost identical to that obtained for an untreated HOPG electrode. Based on these results, it is concluded that electropolymerization of thiophene played an important role not in the phase transfer kinetics of lithium-ion but in reduction of the electrolyte decomposition at a graphite electrode.     

Effect of treatment pressure on structures and properties of PMIA fiber in supercritical carbon dioxide fluid

The effects of treatment pressure on the structures and properties of PMIA fiber were investigated by Scanning electron microscopy, Dynamic wetting measurements, Fourier transform infrared spectrometry, X‐ray diffraction, thermogravimetric analysis, and mechanical properties test technology in supercritical carbon dioxide. The results indicated that the surface morphology, the water contact angle, the interaction of macromolecules, the crystal structure, the thermal property, and tensile strength of PMIA fibers were changed during supercritical carbon dioxide treatment, particularly the surface morphology and the wettability of fiber changed the most obviously with the increase of treatment pressure. Furthermore, the thermal property and tensile strength of treated PMIA fiber sample were improved in comparison with those of untreated sample. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41756.     

Effect of physico-chemical conditions on the properties of zeolite microparticles used in pulp and paper applications

Zeolites are framework aluminosilicates that have been proposed as a replacement for bentonite in microparticle retention systems. It has been claimed in many patents that zeolite can improve sheet formation in fine paper manufacturing. However, this improvement was not observed in mechanical grades. These experimental results, and also theoretical evidence, suggest that papermaking pH plays an important role in zeolite efficiency. In consequence, the effect of pH and temperature on the chemical properties of zeolite and bentonite microparticles was determined. Streaming potential, conductivity, and pH were measured while microparticle solutions were gradually acidified to pH 5. Samples were also taken at specific pH values to measure the cationic demand. Results showed that a gradual reduction of pH caused several modifications to zeolites. The first step was the neutralization of free hydroxyl ions in solution. The second step was an irreversible exchange of the charge-compensating sodium ions by hydrogen ions on the inner and outer surface of microparticles. Finally, dealumination of the zeolites occurred. It was determined that neutralization must be completed before ion-exchange can begin. However, ion-exchange and dealumination occurred simultaneously. Between pH 7.5 and 9, zeolites had more anionic sites than bentonite (around 0.8 meq/g vs. 0.5 meq/g). The higher surface charge of zeolites might partly explain their efficiency in microparticle systems. On the other hand, under pH 7.5, the anionic charge of zeolite samples rapidly decreased while that of bentonite was stable. The effect of temperature was also studied in the 25 to 55 °C range. Generally, a temperature rise promoted a greater dissociation of the surface hydroxyl groups and an acceleration of ion-exchange and dealumination processes.